// Copyright (c) 2012 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef BASE_ANDROID_JNI_ANDROID_H_
#define BASE_ANDROID_JNI_ANDROID_H_

#include <jni.h>
#include <sys/types.h>

#include <string>

#include "base/android/scoped_java_ref.h"
#include "base/atomicops.h"
#include "base/base_export.h"
#include "base/compiler_specific.h"

namespace base {
namespace android {

// Used to mark symbols to be exported in a shared library's symbol table.
#define JNI_EXPORT __attribute__((visibility("default")))

    // Used to disable manual JNI registration in binaries that prefer to use native
    // JNI exports for startup performance. This is not compatible with the crazy
    // linker and so defaults to off. Call DisableManualJniRegistration at the very
    // beginning of JNI_OnLoad to use this.
    BASE_EXPORT bool IsManualJniRegistrationDisabled();
    BASE_EXPORT void DisableManualJniRegistration();

    // Contains the registration method information for initializing JNI bindings.
    struct RegistrationMethod {
        const char* name;
        bool (*func)(JNIEnv* env);
    };

    // Attaches the current thread to the VM (if necessary) and return the JNIEnv*.
    BASE_EXPORT JNIEnv* AttachCurrentThread();

    // Same to AttachCurrentThread except that thread name will be set to
    // |thread_name| if it is the first call. Otherwise, thread_name won't be
    // changed. AttachCurrentThread() doesn't regard underlying platform thread
    // name, but just resets it to "Thread-???". This function should be called
    // right after new thread is created if it is important to keep thread name.
    BASE_EXPORT JNIEnv* AttachCurrentThreadWithName(const std::string& thread_name);

    // Detaches the current thread from VM if it is attached.
    BASE_EXPORT void DetachFromVM();

    // Initializes the global JVM.
    BASE_EXPORT void InitVM(JavaVM* vm);

    // Returns true if the global JVM has been initialized.
    BASE_EXPORT bool IsVMInitialized();

    // Initializes the global ClassLoader used by the GetClass and LazyGetClass
    // methods. This is needed because JNI will use the base ClassLoader when there
    // is no Java code on the stack. The base ClassLoader doesn't know about any of
    // the application classes and will fail to lookup anything other than system
    // classes.
    BASE_EXPORT void InitReplacementClassLoader(
        JNIEnv* env,
        const JavaRef<jobject>& class_loader);

    // Finds the class named |class_name| and returns it.
    // Use this method instead of invoking directly the JNI FindClass method (to
    // prevent leaking local references).
    // This method triggers a fatal assertion if the class could not be found.
    // Use HasClass if you need to check whether the class exists.
    BASE_EXPORT ScopedJavaLocalRef<jclass> GetClass(JNIEnv* env,
        const char* class_name);

    // The method will initialize |atomic_class_id| to contain a global ref to the
    // class. And will return that ref on subsequent calls.  It's the caller's
    // responsibility to release the ref when it is no longer needed.
    // The caller is responsible to zero-initialize |atomic_method_id|.
    // It's fine to simultaneously call this on multiple threads referencing the
    // same |atomic_method_id|.
    BASE_EXPORT jclass LazyGetClass(
        JNIEnv* env,
        const char* class_name,
        base::subtle::AtomicWord* atomic_class_id);

    // This class is a wrapper for JNIEnv Get(Static)MethodID.
    class BASE_EXPORT MethodID {
    public:
        enum Type {
            TYPE_STATIC,
            TYPE_INSTANCE,
        };

        // Returns the method ID for the method with the specified name and signature.
        // This method triggers a fatal assertion if the method could not be found.
        template <Type type>
        static jmethodID Get(JNIEnv* env,
            jclass clazz,
            const char* method_name,
            const char* jni_signature);

        // The caller is responsible to zero-initialize |atomic_method_id|.
        // It's fine to simultaneously call this on multiple threads referencing the
        // same |atomic_method_id|.
        template <Type type>
        static jmethodID LazyGet(JNIEnv* env,
            jclass clazz,
            const char* method_name,
            const char* jni_signature,
            base::subtle::AtomicWord* atomic_method_id);
    };

    // Returns true if an exception is pending in the provided JNIEnv*.
    BASE_EXPORT bool HasException(JNIEnv* env);

    // If an exception is pending in the provided JNIEnv*, this function clears it
    // and returns true.
    BASE_EXPORT bool ClearException(JNIEnv* env);

    // This function will call CHECK() macro if there's any pending exception.
    BASE_EXPORT void CheckException(JNIEnv* env);

    // This returns a string representation of the java stack trace.
    BASE_EXPORT std::string GetJavaExceptionInfo(JNIEnv* env,
        jthrowable java_throwable);

} // namespace android
} // namespace base

#endif // BASE_ANDROID_JNI_ANDROID_H_
